It’s a two-sided problem. For businesses, parking lots are often underutilized and expensive. For consumers, parking is often expensive or difficult to find in certain areas.
An app where individual businesses can sign up to allow people to park in their parking lots. They could limit the areas, costs, etc.
College campuses are known for not having enough parking. Nearby restaurants could open up their parking lots at slow times to gain additional income from an unused asset (their parking lot). They could easily adjust the hours that parking is available via an easy-to-use app or web solution.